Refrigeration



Oct. 25, 1932. F. o. PELJlER ET AL 1,884,187

REFRIGERATION Filed July 6, 1928 8 Sheets-Sheet 1 Oct. 25, 1932. y F. D.PELTIER ET AL I 1,384,137

REFRIGERATION Filed July 6. I928 85heets-Sheet 2 m\ \ymk m momk Oct. 25,71932. F. D. PELTIER ET AL REFRIGERATION Filed July 6/ 1928 8Sheets-Sheet 3 F. o. PELTIER ET AL 1;834137 REFRIGERATION Filed July 6,1928 8 Sheets-Sheet 4 t @INVENTORS) M @325 M Z M u/ 12W M #47; ATTORNEYOct. 25, 1932. F. o. PELTIERY E'ITAL 1,884,187

REFRIGERATION 1 Filed July 6, 192s SShQe-ts-Sheet 5 1932- v F. o.PELTIER ET AL 1,884,137

REFRIGERATION Filed July 6. 1928 8 Sheets-Sheet 7 &

1 1 V I M u Oct. 25 1932.v F. D. PELTIER ET AL REFRIGERATION Filed July6, 1928 8 Sheets-Sheet 8 MN W Patented Oct. 25, 1932 UNITED STATESPATENT OFFICE FRANK DESNOYEBS PELTIER AN D CLYDE EDWARD PLOEGEB, O1EVANSVILLE, INDIANA, ASBIGNORS TO SERVEL, INC., 01 NEW YORK, N. Y ACORPORATION OF DELAWARE REFRIGERATION Application filed July 8, 1928.Serial No. 290,871.

This application is a continuation in part of application, Serial No.152,902, filed December 6, 1926, and relates back to this application,and to application, Serial No. 152,339, filed December 3, 1926, nowPatent No. 1,788,343, granted J anua'ry 6, 1931, for common subjectmatter and the rights instant thereto.

Our invention relates to refrigerating apparatus and more particularlyto the type of apparatus embodying a closed cycle including compressor,condenser and evaporator. Still more particularly our invention relatesto the evaporator of such a system.

Amongst various objects of our invention are: To produce a novel cycleof flow for refrigerant fluid; to provide a novel method and apparatusfor lubricating a refrigeration system and for conducting lubricantwithin re frigeration apparatus; the simplification of manufacturing andstandardizing of refrigcrating equipment an improved multiple system ofrefrigeration; a system of refrigeration which is simple in number andconstruction of parts, the parts of which are of such nature and sodevised that the apparatus as a whole is more rugged and less liable toget out of order than previous devices of this class while maintaining ahigher efiiciency of operation; to produce a direct and positive flow ofrefrigerant with advantages accruing thereto while controlling theflowin a manner such that refrigeration is produced in an efficientmanner independently of the parts of the system collateral toevaporation; to positively return refrigerant from a float valve chamberto the compressor; to provide an arrangement wherein a standard manifoldmay be used with various lengths of tubing for different refrigerativecapacities; and in general to improve the operation of refrigeratingapparatus.

With the above and other objects in view, the invention consists in thenovel features of construction, arrangement of parts and combination ofelements hereinafter described and such variations thereof as fallwithin the scope and spirit of invention and methods and processesinvolved in the operation of such apparatus.

passageway 27 which constitutes a portion of The invention is describedwith reference to the accompanying drawings of which:

Fig. 1 shows more or less diagrammatically a refrigeration systemembodying the principles of invention with novel parts shown more indetail;

Fig. 2 shows the system of Fig. 1 and in addition thereto means forreturning lubricant from the evaporator to the compressor Fig. 3 shows,on an enlarged scale, the construction of a part of the apparatus ofFig. 2;

Fig. 4: shows a modification of the lubricant return means;

Fig. 5 shows another modification of the lubricant return means;

Fig. 6 shows a modification of a pressure drop member forming part ofthe lubricant return means Fig. 7 is a top view of an evaporatorassembly embodying various inventive features Fig. 8 is a front view ofthe evaporator assembly of Fig. 7 shown suspended in a refrigeratorcabinet;

Fig. 9 is a cross-section of a part of the apparatus of Fig. 7;

Fig.- 10 is a side view of the evaporator assembly of Fig. 8.

Fig. 11 shows the lubricant return means of Fig. 2 applied to adifferent form of evaporator;

Fig. 12 shows a multiple system with evaporator sections connected inseries;

Fig. 12a is a top view of a part of one of the sections of Fig. 12;

Fig. 13 shows a multiple system with evaporator units connected inparallel;

Fig. 14 shows a preferred form of manifold shell; and

Fig. 15 shows an adjustment for the orifice.

Referring more particularly to Fig. 1, an electric motor 2 drivescompressor 3. Compressor 3 receives expanded gaseous refrigerant fromconduit 24 and supplies compressed refrigerant throu h conduit 25 tocondenser 4 which may fie cooled in any desired manner, either by wateror by air, though preferably by air. Condenser 4 is connected by meansof conduit 7 with a valve member 23. Valve member 23 has a central acontinuous passageway, a part of which is within the end head 11 offloat manifold 10, said passage being indicated at 26. Passageway 26 isconnected to evaporator coil 15. Evaporator coil 15 is formed of onecontinuous pipe and its outlet end is connected to a passageway formedwithin the other head 16 of float manifold 10, opposite to head 11. Theparts hereafter described are also embodied in the apparatus shown inFig. 3 to which reference may also be had.

Valve member 23 is scewed into a recess 28 formed in head 11. The end ofpassage 27, which is preferably restricted as shown in Fig. 3,constitutes a valve seat indicated at 31. Valve seat 31 co-operates witha needle valve 22. Recess 28 is formed at right angles to passage 26.Needle valve 22 is formed on the end of an extended stem 32. Stem. 32 isalso arranged at right angles to passageway 26. Needle valve 22 ismovable in response to variations of level of liquid within manifold 10,which variations of level are transmitted to the needle valve by meansof a float 18 resting upon the surface of liquid within the floatchamber. This movement is transmitted through lever 19, bell-crank 20and link 21. Float 18 is attached to lever 19 which. is in turn attachedto bell-crank 20 pivoted at on an arm 41. Bell-crank 20 is connected tolink 21 and link 21 is in turn pivotally connected to stem 32 of theneedle valve 22. Stem 32 passes with relatively loose fit, but at thesame time closely, through a passage or bore 34 which connects the innerliquid and vapor space of float manifold 10 with passage 26. Thetightness of stem 32 may be determined in accordance with the desiredbalance of leakage and frictional resistance.

By arranging the conduit from the condenser to the evaporator in partwithin head 11, it is possible, to control needle valve 22 and thuscontrol this conduit by a simple arrangement needing no stufiing boxes,or bellows, or other friction producing or strained part. The amount ofleakage along passage 34: outside stem 32 is of negligible quantity. Bypermitting this slight leakage, a simple construction is obtained. Byarranging the condenser-evaporator connection in part within the headerno leakage is possible from out of the system as a whole.

Head 11 has an opening 12 for the reception of return conduit 24 whichis connected to the intake of the compressor. In conduit 24 is'insertedpressure control switch 6 which may be of known type and which startsand stops the motor on predetermined rise and fall of suction pressure.It will be understood that the system is not limited to any particulartype of control of the motor. Thermostatic control may be used as wellas pressure control.

Reference character 9 designates a refri erator cabinet having insulatedwalls bounding the space to be cooled. The evaporator assembly, includinmanifold 10 with its heads 11 and 16 an coil 15, is entirely placedwithin the cabinet 9 in the space to be cooled. The mode of operation ofthe system shown in Fig. 1 is as follows:

Gaseous refrigerant, such, for example, as

methyl-chloride, compressed in compressor 3 passes into condenser 4where it is liquefied and thence passes through conduit 7 and intopassage 27, assuming that needle valve 22 is away from seat 31 so thatthe valve passage is open. Assuming needle valve 22 to be open, liquidrefrigerant passes into coil 15 and a portion thereof is evaporated.Evaporation absorbs heat from the surroundings and producesrefrigeration. A mixture of vaporous refri erant and liquid refrigerantpasses throu passageway 30 and into the float mani old. The rise ofliquid quantity within the float manifold causes a lifting of float 18and this 0 crates, through the mechanism above descrlbed, to closeneedle valve 22 against seat 31 to a greater or lesser extent, thusdiminishing the flow of liquid refrigerant into the evaporator. Ifneedle valve 22 is entirely closed, no liquid refrigerant passes fromthe condenser through passage 27 and into the evaporator.

Assuming now that needle valve 22 is closed and that thecontrolmech'anism has stopped the motor and compressor. As the space tobe cooled becomes warmer evaporation takes place in manifold 10. Thisincreases the pressure so that the motor is started and at the same timelowers the liquid level so that more liquid refrigerant is admitted intothe evaporator. Float 18 thus operates to maintain a constant, orsubstantially constant, level of liquid within manifold 10. It will benoted that both manifold 10 and coil 15 partake in evaporation andtherefore these two members together may be said to constitute theevaporator.

By means of the arrangement above described a direct positive flow isobtained through the evaporator coil. At the same time the arrangementis such that the evaporator coil is susceptible to variousconfigurations. The advantage of positiveness of float control isobtained in combination with the other features of positive flow andadaptability of structural formation.

In order to take care of lubricant for the refrigeration system aboveoutlined, we have devised the arrangement shown in Fig. 2 which isparticularly suited to cooperate with the system above defined. In Figs.1, 2 and 3 like reference characters designate like parts. The system ingeneral will be understood from the above description. In

Fig. 2 tube 24, connected to the suction side of the compressor, isextended through head 11 into manifold 10 within the vapor spacethereof. Within tube 24 is situated a restricted portion 31. Thisrestricted portion, in the embodiment shown, is formed as the contractedortion of a Venturi tube 25. The Venturi tidie has a graduallycontracting passageway towards the restricted portion and a graduallyexpanding passageway away from the restricted ortion as ischaracteristie with Venturi tu es. The restricted portion of the Venturitube, otherwise known as the throat, has connected thereto a tube 26 ofrelatively small internal diameter or bore which extends below thesurface level of liquid refrigerant within manifold 10.

The system in Figs. 2 and 3 is intended to contain a refrigerant and alubricant of such nature that, in operation, the lubricant is dissolvedin, or is mulsified in. the refrigerant. ltfethyl-chloride is preferablyused as the refrigerant and a mineral oil as the lubricant.

In the system shown in Fig. 1, without any means for taking care oflubricant, and, with lubricant contained in the system intended to gothrough the complete cycle. lubricant would assemble in the manifold 10.This lubricant is removed by the arrangement of Figs. 2 and 3. As thevapor passes out of Venturi tube 25 when drawn by the compressor anincrease in velocity is produced at throat 31 and there is acorresponding drop in pressure at this point which produces a suctionacting through tube 26. This suction causes liquid to flow through tube26 and into conduit 24 and thence on to the compressor. The liquidpassing through tube 26 is composed partly of refrigerant and partly ofdissolved or suspended oil. The fluid passing through conduit 24 passesthrough evaporator coil 27 where the liquid refrigerant carried overthrough the suction line is entirely vaporized and passes into thesuction line proper as a gas together with the separated liquid oilwhich it formerly held in solution or suspension. Coil 27 is within thespace to be cooled and is a secondary evaporator. It might be called atail coil or a drying coil.

With the apparatus shown it will be understood -that the oil cannotaccumulate in evaporator coil as a positive flow is created through thiscoil. The oil is made to accumulate in the float manifold 10 from whichthe arrangement including parts and 26 draws the oil back to thecompressor. It will thus be seen that our novel oil return isparticularly well adapted to co-operate with the sys tem comprising thecontinuous coil 15 having the ends thereof isolated and a float at thedischarge end controlling a valve at the inlet end.

The oil entering the evaporating section with the refrigerantaccumulates within the manifold 10 and the concentration of oil in themanifold increases at the beginning of oper tion until a point isreached where the oil drawn through tube 26 equals the entrained. oilentering the evaporator section. Our arrangement therefore automaticallymaintains a proper flow of lubricant.

The invention is not limited to suspended or dissolved lubricant. Fig. 4shows an arrangement adapted for use in a system employing sulphurdioxide as a refrigerant and aving as a lubricant an oil which islighter than sulphur dioxide and which floats on the top of the same. Inthis case tube 26 is extended to the surface of liquid in the manifold10 and the suction in the Venturi tube d 'aws the oil from the surface.By using a tube 26 extending to the bottom of manifold 10 as shown inFig. 5, the invention is applicable to a refri erating system usingethyl-chloride or methyT-chloride with glycerine as a lubricant,glycerine being heavier than ethylchloride or methyl-chloride andinsoluble therein. In either of the two cases illustrated in Figs. 4 and5 the second evaporator 27 is probably not necessary as the-re would notbe suflicient liquid refrigerant entrained by the lubricant and suckedup through tube 26 to the return line to the suction side of thecompressor to require a second evaporator. In these cases opening 14 maybe connected directly by a pipe to the suction side of the compressor.In any case, it is not desired, however. with a reciprocating type ofcompressor, to carry liquid refrigerant into the compressor.

In Fig. 2 we have shown the motor 2 as controlled by a thermostaticmechanism comprising a bulb 42 connected by tubing 43 to a bellows 44,the bulb, tubing and bellows containing a vaporizable fluid andcomprising a switch 45 responsive to vaporization of fluid in bulb 42,situated in the space to be cooled, for closing and opening the motorcircuit. As in the previous case the evaporator is entirely placedwithin the space to be cooled so that evaporation may take place inmanifold 10 due to heat supplied from the surrounding space to becooled. It will be noted that the liquid within manifold 10 is in directheat transmitting relation with the circulating air of the space to becooled.

Fig. 6 shows a restriction or orifice 46 which may be used for the samepurpose as the Venturi tube of conduit 24. When an orifice is used thetube 26 communicates with conduit 24 a short distance in the directionof flow beyond the orifice 46. The use of an orifice causes a permanentpressure drop in the outlet conduit bcyond the orifice. Such connectionhas also an asperating cfl'cct.

Figs. 7, 8, 9 and 10 show an evaporator assembly as built embodying thefeatures of invention above described. The parts corresponding to likeparts of previous figures are designated with like. reference characters. The evaporator assembly comprises the manifold 10, the primaryevaporator coil 15 and the secondary tail coil or evaporator 27, Theassembly is suspended from the roof of cabinet 9 by means of brackets 47and 48. The coils are arranged to one side of the manifold thoughobviously they may be below the manifold. The coils are looped around abox 49 which contains ice trays 50. The coils are preferably arranged inood metallic connection with box 49 as by so dering. The liquid lineleading from the condenser is connected to member 51. A strainer 52 isplaced within member 53 which is in effect a part of head 11 of manifold10. The arrangement of needle valve 22 and its connection with float 18is substantially as above described. The needle valve stem 32 is provided with a series of grooves 54 which serve to diminish leakage pastthe stem from the inside of manifold 10 to the liquid supply passage.Manifold 10 is provided with circumferentially extending axial fins 56which serve to transmit heat from the surrounding atmosphere to theliquid within the manifold. Liquid refrigerant passes through passage27, past needle valve 22 and into the inlet end of coil 15 which islooped as indicated at 57 After passing through coil 15 refri erant isdischarged through connection 58 into the interior of manifold 10.

If desired, orifice 46 may be made adjustable from the outside of thesystem by using a valve like member having a stem extending through asuitable stufling box which can be moved to regulate the size of theorifice opening so that the suction acting through tube 26 may beregulated in order that the proper amount of liquid may be withdrawnfrom manifold 10. Conduit 26 is connected beyond orifice 46 in the lineof flow as has been explained in connection with Fig. 6 and hence, bydecreasing the size of the orifice the suction in tube 26 will beincreased. Thus, for example, in a multiple installation, as is shown inFig. 13, where the pressure in the different return conduits 24 adjacentthe respective evaporators may be different on account of the differentdistances which the evaporators are from the compressor, the orifices 46in the different evaporators may be so adjusted that the suction actingthrough the respective tubes 26 may be the same for each tube. Theoutlet end 60 of tail coil 27 is connected to the suction side of thecompressor.

lVe prefer to use methyl-chloride and a mineral oil in the arrangementof Figs. 7, 8, 9 and 10 as in the case of the previously describedembodiments. The operation will be clear from the above descriptiontaken in connection with the description of previous modifications.

In Fig. 11 we show the oil return of Fig. 2 applied to a loop type ofevaporator as distinguished from the series coil type of evaporator ofFig. 2. In Fig. 11 manifold 10 has a series of loops 61 depending fromthe bottom thereof. The liquid line 7 discharges directly into manifold10 without first going through an evaporator coil. In the arrangement ofFig. 11 the total drop in pressure tween the liquid line and manifold 10takes place through needle valve 22, whereas in the previous embodimentssome of the pressure drop takes place through the needle valve 22 andsome through the evaporator coil. The oil return mechanism removes oilor lubricant from manifold 10 in much the same manner as in connectionwith the previous embodiments. It will be seen that the lubricant returnmechanism is not confined to the series ooil type of evaporatorpreviously described. However, we prefer it in combination with the samebecause, in the apparatus of Fig. 11, the oil return device can not sowell take care of lubricant which is contained in loops 61 whereas inthe arrangement of Fig. 2 there is a continuous force circulationthrough coil 15 which is certain to carry the oil over into manifold 10and to the vicinity of the inlet opening of pipe 26. If desired, icetrays may be placed within loop 61 of Fig. 11 in well known manner andthe manifold shell may be equipped with fins.

It has been above stated that the arrangement in Figs. 1 and 2 with thecoil 15 may be of various lengths and configurations. In Fig. 12 we haveshown an evaporator assembly wherein a plurality of sections 62, 63 and64 are connected in series by means of conduits 65 and 66 and connectedby means of conduits 67 and 68 with manifold 10. The manifold is ofsubstantially the same construction as in the modifications abovedescribed. Sections 62 and 63 are alike and comprise a tube 70 shaped inthe form of an S and to which are attached flue forming members 71 and72. These are shown in Fig. 12a. Section 64 is similar to sections 62and 63 but is of smaller size.

The arrangement shown in Fig. 12 is in tended for refrigeration inlarger cabinets than the household type. This adaptation is particularlyapplicable to so-called commercial installations. While household unitscan be designed for standard refrigerative effects, the requirements ofcommercial work necessitate different evaporator surfaces and differentcapacities. Our invention permits a ready adaptation to differentcapacities for commercial work. Our system is of the flooded type or,probably more correctly, the semiflooded type. Flooded systems usuallyemploy afloat valve which gives a more definite control than that typeof valve which is generally known as expansion valve used on drysystems. In previous arrangements embodying the use of a float valvecomplications have arisen which were overcome by means of the presentinvention. With the adoption of float control for the supply ofrefrigerant to the evaporator, the float and evaporating surface havegenerally been combined in a unitary structure. The float being in thelow pressure evaporator space, this has been deemed necessary or mostexpedient. The result has been that where different loads are concerned,either complete evaporator units, including floats, must be used or anumber of complete units, each with a separate float, must be used. Thedealer or distributor of refrigerating material of this type eithergenerally has on hand a great number of diferent sizes of differentcapacity evaporators, each including evaporating surface and float, thedifferent sizes being: proportionately graded for different capacities.

By means of the present invention we are able to isolate the float andthe float valve in a separate manifold and one size of manifold issuitable for all capacities of evaporator units regardless ofdifferences of capacities. Furthermore the manifold may be used withdifferent sizes and shapes of evaporator tubing. The type of evaporatortubing shown in Fig. 12 1s a known commercial product. It will beevident that various types of tubing and extended surfaces, therefore,may be used. With this system the distributor need only have a fewmanifolds on hand all of the same size, and a series of standardevaporator sections such, for example, as shown at 62 and 63, withpossibly a small number of odd sized section such, for example, as shownat 64.

It will be evident that sections 62, 63 and 64 may be placed alongsideof each other in parallel. This would probably be the preferablearrangement in the average cabinet. They can be placed in a line, asshown in Fig. 12, which would be the preferred way for. certain showcaseinstallations having an extended evaporator in the compartmentordinarily used for ice. For this purpose the arrangement shown in Fig.12 is particularly suitable as it gives a series of vertical fiuesformed by the member 71, 72.

The operation of the apparatus of Fig. 12

' is the same as that in previous modifications.

This modification includes the oil return device and the tail coil 27for evaporating any refrigerant entrained into pipe 26 or otherwisecarried from the manifold in direction toward the compressor.

Referring to Fig. 13 the apparatus described above is shown in anarrangement suitable for use with a plurality of evaporators. As shown,one condenser is employed but it is to be understood that a separatecondenser may be employed for each evaporator, or two evaporatorssupplied from one condenser and one evaporator from another condenser,or any such combinations of condensers and evaporators may be employedwithout departing from the spirit of the invention. lso, any number ofevaporators ber 79.

may be used, three merely being a convenient number for illustration.

Compressed gaseous refrigerant leaves the compressor through conduit 25,is liquefied by condenser 4 and passes into pipe 5. During its passagethrough pipe 5 the liquid refrigerant divides and passes through thevarious pipes denoted by reference character 7. From conduits 7 therefrigerant passes through respective float actuated expansion valves,evaporators 15 and manifolds 10 in the same manner as previouslydescribed with reference to a single manifold system. The amount ofliquid refrigerant entering each evaporator coil through the expansionvalve used, in connection with that coil is dependent on the liquidlevel in the float chamber of that float'actuated expansion valve and isindependent of the liquid level in any of the float chambers or anyother conditions existing in the system.

The vaporous refrigerant after leaving manifold 10 passes through therespective pipes 24 to a common return pipe 14 which is connected to thesuction side of the compressor. Intel-posed in this pipe 14 may be thepressure control switch 6 used to start and stop the motor atpredetermined valuations of pressure in the suction line.

Fig. 14 shows a preferred form of shell for manifold 10. The shell ismade of a single brass plate and is drawn to the form shown making asingle unitary drawn member composing the major portion of the manifold.The flange portion 76 is connected to a suitable head containing theneedle valve and su porting the float. The opening 77 serves or thereception of a member containing'the conduits connected to the manifoldat that end.

Fig. 15 shows an outside adjustment for the orifice as above referredto. 10- designates valve 80 which is adapted to be moved into 1 and outof the orifice to change its size. Stem 78 is connected to a threadedportion 81 which is adapted to be screwed into mem- Packing 82 isinserted between a ring 83 and a threaded retaining member 84. A cap 85fits over the end of member 78. 86 designates a threaded opening for aconnection to the suction line leading to the compressor. This type ofadjustment or similar adjustments may be applied to the orifices of anyof the previously described embodiments of the invention.

While we have shown and described various embodiments of our invention,it will be understood that we are not limited to the apparatus shown ordescribed but that a great many variations are perm ssible withln thespirit and scope of the invention. 1

Having thus described our invention, what we claim is:

1. Refrigerating apparatus comprising, in *ombination, a firstevaporator conduit, means to supply liquid refrigerant to said firstevaporator conduit, a manifold connected to said first evaporatorconduit to receive liquid and vapor therefrom, means to regulate thesupply of liquid refrigerant to said first eva orator conduit to definea liquid space an a vapor space in said manifold, a second evaporatorconduit connected to receive vapor from said manifold, means interposedin the path of flow of vapor from said manifold to said secondevaporator conduit for producing a dro in pressure and a connectionbetween sai liquid space and said means.

2. A refrigerator comprising a cabinet having insulated bounding wallsdefining a space to be cooled, an evaporator within said spacecomprising a first evaporator conduit, means to supply liquidrefrigerant to said first evaporator conduit, a manifold connected tosaid first evaporator conduit to receive liquid and vapor therefrom,means to regulate the supply of liquid refrigerant to said firstevaporator conduit to define a liquid space and a vapor space in saidmanifold, a second evaporator conduit connected to receive vapor fromsaid manifold, a restriction interposed in the path of flow of vaporfrom said manifold to said second evaporator conduit for producingaspace of diminished pressure and a connection between said liquid spaceand said space of diminished pressure for drawing liquid from saidmanifold into said second evaporator conduit, said second evaporatorconduit acting to take up heat from the space to be cooled and toevaporate liquid refrigerant therein.

3. A refrigerator comprising a cabinet having insulated bounding wallsdefining a space to be cooled, an evaporator within said spacecomprising a first evaporator conduit, meansto supply liquid refrigerantto said first evaporator conduit, a manifold connected to said firstevaporator conduit to receive liquid and vapor therefrom, means toregulate the supply of liquid refrigerant to said first evaporatorconduit to define a liquid space and a vapor space in said manifold, asecond evaporator conduit connected to receive vapor from said manifold,a restriction interposed in the path of flow of vapor from said manifoldto said second evaporator conduit for producing a space of diminishedpressure and a connection between said liquid space and said space ofdiminished pressure for drawing liquid from said manifold into saidsecond evaporator conduit, said second evaporator conduit acting to takeup heat from the space to be cooled and to evaporate liquid refrigeranttherein and said manifold comprising a single-walled shell acting totransmit heat directly from the space to be cooled to the liquid withinthe manifold.

4. A refrigerator comprisin a cabinet hav in insulated bounding wallsefining a space to be cooled, an evaporator within said space comprisinga first evaporator conduit, means to supply liquid refrigerant to saldfirst evaporator condult, a valve for controlling the supsure and aconnection between said liquid space and said space of diminishedpressure for drawing liquid from said manifold into said second evaorator conduit, said second evaporator con uit acting to take up heatfrom the space to be cooled and to evaporate liquid refrigerant thereinand said manifold comprising a single-walled shell acting to transmitheat directly from the space to be cooled to liquid within the manifold.

5. A refrigerator comprising a cabinet having insulated bounding wallsdefining a space to be cooled, an evaporator within said spacecomprising a continuous conduit, means to produce flow of fluid throughsaid conduit, a valve at the inlet to said conduit, a manifold forming achamber at the exit from said conduit, means responsive to variations ofliquid level in said chamber operable to control said valve, a dischargeconnection for removing vapor from one part of said chamber, saidconnection having a restricted portion oper ating to produce a space ofdiminished pressure and a communication between said space of diminishedpressure and a lower part of said chamber.

In testimony whereof, we hereunto aflix our signatures.

FRANK DESNOYERS PELTIER. CLYDE EDWARD. PLOEGER.

